The present invention relates to compound archery bows, and more particularly, to an archery bow draw board for pulling on the bow string to measure draw weight and for tuning, maintenance and repair of a compound bow.
Referring to prior art FIG. 1, a typical compound archery bow 1 includes a centrally located riser 2 that has generally outwardly extending limbs 3. At the ends of the limbs are located symmetrically related pulley 4 and eccentric cam 5. Some compound bows 1 have the pulley 4 replaced with a second matching cam 5. Cable 6 of a bow string 7 is anchored and wrapped around the pulley 4 and cam 5. The other cable 6 ends have located thereon bow string 7. Optionally, the central region of the bow string 7 and the end portions of the cabling 6 are wrapped with serving thread 8 to prevent wear of these areas. A release loop 9 may be mounted in the middle of the bow string 7 for attachment of a hand release to shoot the bow 1.
Archery bows 1 require tuning, repair and maintenance for continuous accurate shooting. The appropriate draw length of the bow 1 must be set up for the archer. The cables must come off the respective pulley 4 and cam 5 in equally tuned fashion so that the shooting forces that come off the limbs 3 are even between both limbs 3. Occasionally, the serving 8 must be replaced after significant wear, or if unraveling occurs. Bow strings 7 and cabling 6 also stretch over time requiring re-anchoring to the pulley 4 and cam 5 or total replacement. Sometimes it is desired to twist the bow string 7 for proper alignment of the hardware mounted thereon, like a peep sight.
In the past, a common method of checking the actual draw weight or poundage to pull the bow string 7 back to the shooting position required an upper solid structure, like a beam A, to which is mounted a spring scale B in a swivel fashion. The archery shop technician would hook the bow string 7 onto the scale B and with his hands C pull the bow downwardly while observing the output of the scale B. A hand-held scales are also available. While this method has worked well, no tuning, maintenance, repair or adjustment can be made by the technician during this measurement effort.
A bow press 10 is a necessary tool for all archery shops and advanced archers who tune and maintain their own bows 1. Co-owned U.S. Pat. Nos. 8,387,600 and 8,505,523 illustrate the construction and operation of a bow press 10 which are incorporated herein by reference. In simple terms, a bow press 10 is shown in FIG. 2. Bow press 10 has an elongate main beam 26 which support first and second pivot arms 28, 30 supported from below by laterally adjustable pivot arm brackets 56, 58 at least partially mounted on threaded adjustment rod 64 which is rotatable by crank 118. Rotation of crank 118 moves the pivot arm brackets inwardly or outwardly for proper fitting of the particular bow 1 on the bow press 10. Above the brackets 56, 58 are located inside surface supports 78, 80 for locking the bow 1 onto the bow press 10 for service and adjustments. Limb deflectors or ears 88, 96 are adjustably mounted on pivot arms 28, 30 and are capable of pressing and holding against the limbs 3. An upstanding screw jack 50, with an extendable portion 113, is adjusted upwardly or downwardly by a crank 115. Links 108, 110 connect the pivot arms 28, 30 to the extendable portion 113 of the screw jack 50 as to move the limb ears 88, 96 inwardly and outwardly to facilitate cable 6 and bow string 7 relaxation for performing tuning, repair and maintenance functions.